When a driver is seated in a vehicle, he should adjust all of the interior and exterior rearview mirrors according to his need. The rearview mirror can be adjusted manually or automatically by pushing buttons. After the adjustment of rearview mirrors is done, the view angle of each rearview mirror seen by the driver is constant, and it is difficult and also dangerous for the driver to further change the view angles while driving.
In practice, when a driver would like to change to another lane, turn to another direction or overtaking a car, he will need to realize more about the situation of the adjacent lane to see whether there is any vehicle oncoming. Therefore, the horizontally turning of the rearview mirror toward the target lane will be helpful for the lane-changing or overtaking operation. In addition, while moving up or down a slope, it is advantageous to turn the rearview mirror vertically to obtain a view range similar to that on the flat road.
Taiwanese Patent Publication Nos. 388377, 465498, 448874 and 448875 issued to Sun (Taipei, Taiwan, R.O.C) and 459637 to Hsieh (Hsinchu, Taiwan, R.O.C), which are incorporated herein for reference, disclose the automatic movement of rearview mirrors according to the driving situations of a vehicle so that the driver can have an improved view angle without manually adjusting the rearview mirrors while driving. These techniques, although create a flexible view range for the vehicle, does not solve the problem thoroughly.
For example, when the driver is changing his vehicle to the immediately adjacent lane, a small degree of rotating angle of the rearview mirror is enough to realize the situation of the adjacent lane. On the contrary, when the vehicle has to run across more lanes continuously, the driver may need to realize more about the further adjacent lane. For another example, when the slopes that the vehicle is climbing up are different, the required rotating angles of the rearview mirror are supposed to be different in order to obtain a view range similar to that on the flat road. Therefore, it is preferred that the view range of the rearview mirror can be optionally adjusted with the change of the vehicular traveling status. The prior art, however, move the rearview mirror only between two fixed positions, i.e. the initial position and the working position, and thus are not flexible enough. Moreover, the time required for returning to the initial position for the normal driving mode would be relatively long if the preset rotating angle from the initial position to the working position is relatively large.
Further, some of the prior art do not disclose the returning timing of the rearview mirror back to the initial position, which is definitely necessary after recovering to the normal driving mode, and the other just disclose that the rearview mirror returns to the initial position when the rotation-enabling device, e.g. the indicator light, for enabling the rearview mirror to rotate is disabled. This is also inflexible in practice.